Jupiterc.1200, "supreme deity of the ancient Romans," from L.Iupeter, from PIE*dyeu-peter- "god-father" (originally vocative, "the name naturally occurring most frequently in invocations" [Tucker]), from *deiw-os "god" (see ZEUS (Cf.Zeus)) + peter "father" in the sense of "male head of a household" (see FATHER (Cf.father)). Cf. Gk.Zeu pater, vocative of Zeus pater "Father Zeus;" Skt.Dyauspita "heavenly father." The planet name is attested from late 13c. Jupiter Pluvius "Jupiter as dispenser of rain" was used jocularly from 1864.

Jupiter — Ju pi*ter, n. [L., fr. Jovis pater. See {Jove}.] [1913 Webster] 1. (Rom. Myth.) The supreme deity, king of gods and men, and reputed to be the son of Saturn and Rhea; Jove. He corresponds to the Greek Zeus. [1913 Webster] 2. (Astron.) One of the… … The Collaborative International Dictionary of English